The invention concerns a wood pulp grinder and particularly concerns means for retaining the pulp suspension forming liquid at the wood delivery area.
One such pulp grinder is known from German Pat. No. 445 717. This grinder is designed so that the wood can be soaked, preferably in warm water, directly in the wood-supply chute, rather than in a vat that is separate from the grinder housing. The patent specifies soaking the wood for one or even two hours in water in the wood-supply chute to obtain a satisfactory moisture content in the wood before it arrives at the grinder stone. It is obvious that the grinding must be very careful to attain such long soaking times in the supply chute, so that no damp should be expected in the grinding zone as a result of the heat generating by grinding.
Preventing the local overheating of the wood in the grinding zone by directing a stream of water onto it is also common in contemporary pulp grinders.
To ensure that there is a sufficient quantity of water in the grinding zone, it is known to supply water and/or to supplement the water in the grinding zone through passages in the grinder stone. See Austrian Pat. No. 134 130 and U.S. Pat. No. 2,929,568, for example.